package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import jakarta.annotation.PostConstruct;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
@RequiredArgsConstructor
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    private final ISeckillVoucherService seckillVoucherService;

    private final RedisIdWorker redisIdWorker;

    private final RedissonClient redissonClient;

    private final StringRedisTemplate stringRedisTemplate;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT =new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    //创建阻塞队列
    private final BlockingQueue<VoucherOrder> orderTasks=new ArrayBlockingQueue<>(1024*1024);
    //创建线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR
            = Executors.newSingleThreadExecutor();
    //获取线程代理对象
    private IVoucherOrderService proxy;
    @PostConstruct
    private void init(){
        // 创建消费者组（假设使用RedisTemplate）
        // stringRedisTemplate.opsForStream().createGroup("stream.orders", "g1");
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        String queueName="stream.orders";
        @Override
        public void run() {
            while(true){
                try {
                    //获取消息队列中的消息
                    // VoucherOrder voucherOrder = orderTasks.take();
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    if(list==null||list.isEmpty()){
                        continue;
                    }
                    //解析消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();

                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(),true);
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while(true){
                try {
                    //获取消息队列中的消息
                    // VoucherOrder voucherOrder = orderTasks.take();
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    if(list==null||list.isEmpty()){
                        break;
                    }
                    //解析消息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> value = record.getValue();

                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(value, new VoucherOrder(),true);
                    handleVoucherOrder(voucherOrder);
                    //ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName,"g1",record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    try {
                        TimeUnit.MILLISECONDS.sleep(5000);
                    } catch (InterruptedException ex) {
                        throw new RuntimeException(ex);
                    }
                }
            }
        }
    }


    /*private class VoucherOrderHandler implements Runnable{

        @Override
        public void run() {
            while(true){
                try {
                    //take() 阻塞等待
                    VoucherOrder voucherOrder = orderTasks.take();
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }*/

    /**
     * 处理订单
     * @param voucherOrder
     */
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        RLock lock = redissonClient.getLock("order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if(!isLock){
            log.error("用户{}的订单{}创建失败",userId,voucherOrder.getId());
        }
        //获取代理对象
        try {
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {

        //为0有购买资格
        long orderId = redisIdWorker.nextId("order");
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),String.valueOf(orderId));
        //判断是否为0
        int r = result.intValue();
        //不等于0没有购买资格
        if(r != 0){
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //返回订单id
        return Result.ok(orderId);
    }

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString());
        //判断是否为0
        int r = result.intValue();
        //不等于0没有购买资格
        if(r != 0){
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }
        //为0有购买资格
        long orderId = redisIdWorker.nextId("order");
        //TODO:下单信息保存到阻塞队列中
        VoucherOrder voucherOrder = VoucherOrder.builder()
                .voucherId(voucherId)
                .userId(userId)
                .id(orderId)
                .build();
        //获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //将订单添加到阻塞队列
        orderTasks.add(voucherOrder);
        //返回订单id
        return Result.ok(orderId);
    }*/
    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        //是否已经开始
        if(voucher.getBeginTime().isAfter(LocalDateTime.now())){
            //尚未开始
            return Result.fail("秒杀尚未开始");
        }
        //是否已经结束
        if(voucher.getEndTime().isBefore(LocalDateTime.now())){
            //结束
            return Result.fail("秒杀已经结束");
        }
        //判断库存是否充足
        if(voucher.getStock() < 1){
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
        RLock lock = redissonClient.getLock("order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if(!isLock){
            return Result.fail("禁止重复下单");
        }
        //获取代理对象
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            lock.unlock();
        }
    }*/

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        //查询订单
        long count = query().eq("user_id", userId)
                .eq("voucher_id", voucherId)
                .count();
        if(count>0){
            log.error("用户已经购买过一次了");
        }

        //扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherId)
//                .eq("stock", voucher.getStock())//乐观锁
                .gt("stock",0)//乐观锁
                .update();
        //创建订单
        if(!success){
           log.error("库存不足");
        }
        save(voucherOrder);
    }
}
